MIT makes incandescent light bulbs more efficient than LEDs.

http://www.telegraph.co.uk/news/sci...-MIT-makes-them-more-efficient-than-LEDs.html

Can the indoor light that we loved in the 1970's be coming back?

We can play Led Zeppelin, drive in our Classic cars, and maybe even return to the retro indoor light that we grew up with and love and miss so much?

It's pretty, I wonder if having the filament sandwiched between crystal plates like that means that's what the whole "bulb" would look like..

Will they be as impact resistant and affordable for flashlight applications?

A future for incandescents?

Just caught the following article on the BBC:

http://www.bbc.co.uk/news/science-environment-35284112

Claimed efficiency of 3x that of LED, now that would be interesting if it was a reality.

Re: A future for incandescents?

MikeSalt said:

Just caught the following article on the BBC:

http://www.bbc.co.uk/news/science-environment-35284112

Claimed efficiency of 3x that of LED, now that would be interesting if it was a reality.

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I'm merging this thread with an existing thread on this topic & moving it to the /Fixed Lighting/ subforum; the articles are somewhat different so it wouldn't hurt to include this one in the existing thread.

Yawn, another article written by a journalist that doesn't know what they are talking about. Too little, too late.

LED bulbs are ~25% efficient or more, not 14%. You can already buy LEDs that are 40% efficient, and better efficiencies are already in the pipeline.

This would be exciting 10-15 years ago. As it is, I just can't see any way this could be successfully commercialized. There may some esoteric application this is good for, but home lighting is probably not one of them.

CoveAxe said:

Yawn, another article written by a journalist that doesn't know what they are talking about. Too little, too late.

LED bulbs are ~25% efficient or more, not 14%. You can already buy LEDs that are 40% efficient, and better efficiencies are already in the pipeline.

This would be exciting 10-15 years ago. As it is, I just can't see any way this could be successfully commercialized. There may some esoteric application this is good for, but home lighting is probably not one of them.

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Nonsense. You can't make a 40% efficient LED that has beautiful light. LEDs with a high CRI have a lower efficiency. If you could get an incandescent bulb up to 40% efficiency it would clobber LEDs.

Nonsense. You can't make a 40% efficient LED that has beautiful light. LEDs with a high CRI have a lower efficiency. If you could get an incandescent bulb up to 40% efficiency it would clobber LEDs.

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Fair enough, but this still doesn't change the fact that LEDs are still continuously improving in light quality, efficiency, and lifetime, and have decades and billions of dollars of investment and R&D behind it. The best efficiency this group has shown is 6.6%. The 40% is completely hypothetical, and therefore the real-world efficiency is likely going to be lower.

This is also assuming that the IR reflective layers don't change the color output of the light. Then also factor in how much the average person cares about the barely noticeable difference in light quality and are willing to pay a premium for it and you can see the market for this drying up quickly.

This is a neat academic project and may have some useful applications like furnace or oven windows so that IR energy isn't escaping out, but this is way too late for general lighting. It would require an enormous amount of investment and manpower just to bring it up to current LED efficiency standards, by which time LED will be another step ahead.

I see potential in the MIT technology.

Reliability, earth-friendliness and cost can all be improved by removing complicated electronic circuits, cutting down on plastic, and returning to a mostly glass/metal construction.

Think about all the dirty factories in China pumping out our current state-of-the-art LED bulbs. They need plastic. They need metals. They need semiconductors. They need passive components. They need assembly work. They need solder. LED bulbs are resource intensive, and they are made in a country that doesn't really pay much mind to pollution control.

Then when the LEDs get here, they are either expensive or cheap, reliable or unreliable, cast a poor CRI light or do fairly well, don't always dim so well, constantly are changing designs.

Don't get me wrong, nearly my entire house is all LED. They are "OK", but I would be so willing to consider the MIT bulbs if they ever came to market, even at parity with LED efficiency. Even better would be if they could be made here in USA again.....

A valid concept. If all of the infra red can be bounced back to the filament to contribute to visible-light output the efficiency gain would be dramatic. This has already been done commercially to some degree with "HIR" automotive headlamps. I put some on a previous car; it was a way to boost the light output without having to rewire for higher wattage.

This article contains two major annoyances for me:

1. Confusing CRI with color temperature. No, incandescent lamps do not "match the hue of objects seen in natural daylight."
2. Expressing performance as percent efficiency. Yes, you can formally define "efficiency" with respect to 555 nm monochromatic light, but that's a meaningless standard if your goal is to produce blackbody-ish white light. It's better to just compare luminous efficacy (lumens/watt), color temperature, and CRI separately.

The article also follows the depressingly familiar journalistic pattern of taking the speculated future performance of a lab prototype and declaring it a replacement for a mature, commercial technology. It's not as bad as the case of the Lockheed fusion reactor, which "existed" only on paper, but it's close.

Problem with incandescent is all the wattage wasted due to resistance in the wire that leads to the wire heating up...I do not see how adding two crystal plates will change this variable. To me, this is scientists clinging to old technology hoping to out do the LEDs...

cdrake261 said:

Problem with incandescent is all the wattage wasted due to resistance in the wire that leads to the wire heating up...I do not see how adding two crystal plates will change this variable. To me, this is scientists clinging to old technology hoping to out do the LEDs...

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The plates have a series of reflective layers that reflect IR radiation back to the filament. This means that this otherwise wasted radiation is used to keep the filament hot, requiring much less electrical power to glow.

It's a theoretically sound idea, but I just don't see it ever gaining a foothold because of the investment that would be required to get it competitive with LEDs.

CoveAxe said:

The plates have a series of reflective layers that reflect IR radiation back to the filament. This means that this otherwise wasted radiation is used to keep the filament hot, requiring much less electrical power to glow.

It's a theoretically sound idea, but I just don't see it ever gaining a foothold because of the investment that would be required to get it competitive with LEDs.

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To even get the wire inside the bulb to put out any IR radiation, you will still need to push some decent power through a wire and overcome the resistance. I do not believe this technology will ever be as efficient as LEDS, nor take any foothold in the market...I've been wrong before, so who really knows.

To even get the wire inside the bulb to put out any IR radiation, you will still need to push some decent power through a wire and overcome the resistance.

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I think you have the wrong idea in your head. That's not how that works. You don't "overcome the resistance". That has nothing to do with it.

An incandescent bulb loses most of its power through infrared radiation. This technology simply reflects that back internally so it's used to help heat the filament rather than get radiated away. If conduction/convention losses weren't a problem, you could light this up to a 100W equivalent with just a few watts of power. The idea behind it is sound. In theory you could make this more efficient than current LEDs.

The problem is that their reflective coating is difficult to make among other things, and they haven't demonstrated high efficiencies. It would require a lot of investment for very little gain. For that reason I agree that it's unlikely to go anywhere except for some esoteric applications.